LOS ANGELES -- A group of analysts and reporters got an extensive sneak peek at Windows 7 from Microsoft executives today, but don't look for any research reports or articles about the session right away. To get the early preview of Microsoft's next operating system, those who attended had to agree not to disclose what they saw until it's shown publicly here later this week.

Non-disclosure or "NDA" briefings, as they're known, are common in the tech industry and on the Microsoft beat. But given the high level of interest in the next Windows version, and the chatty nature of some analysts and reporters, it will be interesting to see if this one survives without leaks. The session -- in an ironically windowless hotel conference room -- lasted about six hours, according to one person who was there. Windows executives including Steven Sinofsky and Mike Nash gave presentations, and others gave live demos.

Without going into details about what was shown, the person said the early version of Windows 7 looked good. As expected, the person said, it clearly builds off Windows Vista, but with enough new stuff to qualify as a major upgrade. But for Microsoft, at least, this might be the best news of all: There were reportedly no crashes or other major glitches during the demonstrations.

The rest of us are expected to get our first glimpse of Windows 7 on Tuesday morning.